During wafer fabrication, wafers are commonly transferred between a wafer chuck and a robotic arm by mechanical devices along a dual positioning axis vertical to the chuck's wafer holding face. The mechanical devices lift/lower a wafer between the chuck's wafer holding face and a loading level, where the wafer may be accessed by a robotic arm for further transportation. Such mechanical devices that employ pins to contact the bottom side or the circumference of the wafer for transfer along the dual positioning axis are commonly referred to as pinlifter assemblies.
A pinlifter assembly needs to be simple and compact while providing a smooth and balanced motion of each pin contacting the wafer. In addition, the pinlifter assembly needs to be designed around other features affiliated with the positioning and holding of the wafer. Such features may include vacuum systems for holding the wafer onto the wafer holding face and precision motion systems for moving the chuck together with the wafer. Such a motion system may be for example an X-Y stage or a rotary stage. All these limiting aspects need to be accounted for by the design of the pinlifter assembly. At the same time, the pinlifter assembly is desirably compact and highly integrated in the wafer chuck. The present invention addresses these needs.